Apparatus for assigning and estimating transmission symbols

Abstract

An apparatus for assigning transmission symbols to a media data stream of information symbols is described, the media data stream including a first substream for representing media content in a basic quality and a second substream including additional data for representing the media content, along with the first substream, in an improved quality. The apparatus includes a first assigner for assigning first transmission symbols to the information symbols of the first substream and a second assigner for assigning second transmission symbols to the information symbols of the second substream, the first transmission symbols being transmissible, via a transmission channel, with reduced error probability as compared to the second transmission symbols.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation of copending German Application No. 102008029353.9-55, filed Jun. 20, 2008, which is incorporated herein by reference in its entirety.[0002]The present invention relates to transmitting data streams composed of substreams of different levels of significance, as is the case in a scalable video codec, for example.BACKGROUND OF THE INVENTION[0003]In radio networks, for example in mobile radio networks, transmission errors typically depend on the quality of reception. Several concepts have already been known in the field of conventional technology which improve the error-proneness of data transmissions, for example by taking advantage of diversity. For example, current radio transmission systems such as UMTS (universal mobile telecommunication systems), HSPA (high speed packet access), LTE (long term evolution), etc. are trying to make use of the available transmission bandwidth as well as possible by adapti...

AI Technical Summary

Benefits of technology

[0011]According to another embodiment, a method of assigning radio resources to transmission symbols, and assigning transmission symbols to a media data stream of information symbols, the media data stream including a first substream for representing a media content in a basic quality and a second substream including additional data for representing the media content, along with the first data stream, in an improved quality, may have the steps of: assigning first transmission symbols to the information symbols of the first substream; assigning second transmission symbols to the information symbols of the second substream, the first transmission symbols being transmissible, via a transmission channel, with reduced error probability as compared to the second transmission symbols; assigning radio resources to the first transmission symbols and to the second transmission symbols to balance off variable data rates of the first substream and of the second substream; transmitting the first and second transmission symbols as broadcast transmissions, specifically by means of frequency spreading, wherein the transmission symbols of the first and / or second substream(s) are superimposed in a shared frequency range, respectively, and OFDM (orthogonal frequency division multiplexing) transmission, wherein the transmission symbols—superimposed in the shared frequency range—are transmitted via a radio channel as the transmission channel.

[0018]The present invention is based on the knowledge that substreams of scalable coding methods may be modulated differently. The available radio resources may thus be employed more efficiently and be adapted to the levels of significance of the substreams. For example, a scalable video coding process such as H.264 / SVC, for example, may comprise an adaptation to the source. For example, by means of spreading, space-time coding and adaptation of the modulation process to the video signal, embodiments may enable a large video bandwidth and, simultaneously, failure safety and a large range of transmission. In embodiments, existing mobile radio infrastructure may be used for this purpose, for example, which may also be operated at a low transmit power, depending on the embodiment.

[0019]In other words, it is the core idea of the present invention that, e.g., concepts that are known from mobile radio systems and concepts that are known, e.g., from video coding, are combined such that adaptive, flexible and reliable broadcast transmission to a multitude of users is made possible.

Problems solved by technology

In radio networks, for example in mobile radio networks, transmission errors typically depend on the quality of reception.

Video transmission in mobile radio networks constitutes a problem.

In other words, a broadcast transmission is directed at a multitude of users, which does not allow obtaining individual feedback on a transmission quality from each user.

Conventional concepts enabling broadband wireless video transmission in cellular mobile radio architectures at low transmit power both with a large range of transmission and with a high level of failure safety cannot be used in the case of broadcasting due to lack of feedback from the individual subscribers.

Due to the multipath propagation, parts of the signal may erase themselves by destructive superposition and may induce so-called fast fading.

The resulting transmission or bit errors at the receiver may be corrected by adding redundancy, i.e. within the context of channel coding—however, this will be at the price of slower transmission rates.

Shadowings of direct line-of-sight links, which may also be referred to as slow fading, may lead to considerable drops in the receiving power, even in small regions, in the order of magnitudes of several meters.

Images